Wabbler mechanism



DCL 7, E. S k HALL woBBLER MECHANISM Filed Feb. `13, 1939 INVENToR.

Ami Si hl/ Patented Oct. 7, 1941 t UNITED STATES PATENT OFFICE WABBLERMECHANISM Edwin S. Hall, Farmington, Conn.

IApplication February 13, 1939, Serial No. 256,071

I (c1. 'za-so) 20 Claims.

This invention relates to mechanism for the interconversion of pistonreciprocation and shaft rotation in engines and pumps of the classhaving cylinders parallel to the shaft. The object of the invention isto provide improvements in wabbler mechanisms. lThis application is acontinuation in part of my copending application Ser. No. '70,216 filedMarch 23,1936.

vIn discussing parallel cylinder mechanisms, it is convenient todistinguish between a swashplate and a wabbler. Bothare plate-likestructures concentric with and inclined to the shaft. The swashplate isa rotating member ordinarily xed on the shaft. The wabbler does notrotate, being mounted on bearings either on a Z-crankshaft or onswashplate means fixed upon a straight shaft. Ball or roller bearingsmay be used but it is recognized that Iluid film lubricated bearings canbe equally efficient, less expensive, and more durable. An object ofthis invention is to provide fluid film lubricated wabbler bearings ofimproved construction.

Film lubrication in a journal bearing, with the journal assuminganeccentric position in the bearing and the oil-wedge forming betweenconverging cylindrical surfaces, is well-known. This condition occursbest when the load is normal to the journal. But the loading on awabbler bearing is not normal to the wabbler axis, but includes anoverturning couple or moment, and when journal bearings are used on aZ-crank, this cantilever loading tends to cock the journal bearings,producing concentrated loadsvat the ends of the journal instead of thecircumferential Wedge of oil distributed uniformly the whole length ofthe bearing which is necessary for eflicient film lubrication.

Film lubrication ina plain collar thrust bearing, axially loaded, is notpossible because no oil-wedge can form between parallel surfaces,wherefore the lplain collar thrust beaing cannot' carry heavy loadsefficiently. But when a wabbler is mounted on a swashplate of correctdesign, the structure, while similar` in appearance to a. plain collarthrust bearing, functions quite differently. 'lhe loading is not purelyaxial, but includes the aforesaid overturning couple or moment whichoperates to distribute the clearance between the wabbler and theswashplate so y that the surfaces are not parallel but converging in thedirection of motion, making it possible forv oil-Wedge films to form inthe same way they form in a normally loaded journal bearing.

In short, wabbler loading, especially in a normal parallel engine havingworking cylinders at for film lubrication between a wabbler andswashplate are facilitated by piloting the wabbler on a spherical bossof the swashplate, suchva boss permitting the wabbler to swing intoproper position relative to the workingsurlacesmof both swashplate andwabbler andthe clearances between them.

An object of this invention is i to provide imj-.

proved constructions for swashplates vand wabblers to promote fluid filmlubrication between their coacting surfaces. Another object is toprovide aswashplate relatively inexpensive to manufacture and capable ofbeing conveniently machined all over and conveniently a/ttachablel to astraight shaft.

Briefly described, the invention consists of a swashplate meansflxedupon the shaft with a wabbler operably mounted on the swashplate meansin such a manner as to promite fluid film lubrication between them. Twoinversions of the mechanism may be used: that in which the swashplate isa single member between twoY parts of the wabbler; and that in which thewabbler is a single member between two parts of the swashplate.

In the former typel the swashplate has Working surfaces which aresurfaces of revolution relative to the swashplate axis, and a centralspherical boss thru which the shaft passes, the axis` of the shaft beinginclined relative to the swashplate .axis and the center of the spherebeing at the intersection of the two axes. The hole thru the boss andthe facings at the ends of the'hole can be easily machined relative tothe axis of the hole, coinciding with the shaft axis. The

l outer surfaces of the swashplate including lthe spherical boss can bereadily machined relative to the swashplate axis. The spherical boss mayalso serve as a pilot for the wabbler, taking the radial loading, andpermitting the wabbler to swing readily into proper position for thebest `distribution of the working clearance to promote catch the leakagefrom around the boss.

In the alternate type, the wabbler is a single member, mounted on aspherical boss clamped between two swashplate members on the shaft. Withthis construction, oil shields are necessary to maintain floodedlubrication in the wabbler bearings.

With either type of swashplate and wabbler construction, the workingsurfaces may be either plane, spherical, or conical; and the bearingsmay be either plain bearings or slipper bearings. If

Y slipper bearings are used, film lubrication is de- Fig. 2 is atransverse section of the mechanism shown in Fig. 1;

Fig. 3 is a longitudinal section thru a Wabbler and swashplatemechanism, substantially the inversion of that shown in Fig. 1;

Fig. 4 is a longitudinal section thru a Wabbler and swashplatecombination similar to that of Fig. 1, with pivoted slipper bearings;

'Fig'. 5 is a longitudinal section thru a Wabbler and swashplatecombination similar to that of Fig. 3, with pivoted slipper bearings;

Fig. 6 is a longitudinal section thru a wabbler and swashplatecombination of similar type to that of Fig. l, but having sphericalbearin'g surfaces instead of plane; and

Fig. '7 is a longitudinal section thru awabbler and swashplatecombination of similar type to that of Fig. 3, but having conicalbearing'surfaces instead of plane.

Referring to the drawing, in Figs. 1 and 2, swashplate I is fastened onshaft II by splines and conical wedges in a well-known manner.swashplate I0 has a central spherical boss I2 and plane working faces I3and I4. Wabbler I5 is mounted on swashplate I0 and is provided withbearing surfaces coactng with boss I 2 and working faces I3 of theswashplate. Wabbler- I5 is in two parts, with swashplate I0 betweenthem. Oil shields I6 may be provided on Wabbler I5. Wabbler arm I'I andaccompanying parts serve to operably connect Wabbler I to piston memberI8 reciprocable in cylinder I9 parallel to shaft II. Oil is forced byany suitable means into hollow shaft II, and thence by holes to theworking clearance between swashplate I0 and Wabbler I5, and thence thrupassages in Wabbler arms I'I to the other working parts.

In Fig. 3, swashplate member 30 comprises two similarparts 30a and 30bwith spherical boss 30e clamped between them on shaft 3| in any suitablemanner. Wabbler `35 is piloted on spherical boss 30c` and has planebearing surfaces operably engaging the plane faces 33 and 34 ofswashplate 30. companying parts serve to connect Wabbler 35 to pistonmember 38 reciprocable in cylinders 39 and connecting crosshead guidesurface 49, coaxial with cylinders 39 and parallel to shaft 3I. Oil isforced by any suitable means into the arinular space in shaft 3|, andthence by suitable passages to the working clearance between swashplate3U and Wabbler 35. Oil shields 4I together with the centrifugal actionof swashplate member 30 combine to assist in the maintenance of an oilbath in the working clearance between swashplate 3D and Wabbler 35.

Wabbler arm 3'Iand ac- The structure shown in Fig. 4 is similar to thatof Fig. 1 except that slippers 44 are seated in pivot cups in Wabbler 45and have plane bearing faces operably engaging the plane working facesof swashplate 40. Oil holes 46 are provided to carry oil from theinterior of the shaft to the space between swashplate 40 and Wabbler 45in which slippers 44 operate, so that the slippers 44 may always beimmersed in an oil bath.

The structure shown in Fig. 5 is similar to that of Fig. 3 except thatslippers 54 are seated in pivot cups in wabbler 55 and have planebearing faces operably engaging the plane working faces of swashplate50. Oil holes 56 are provided to carry oil from the interior of theshaft to the space between swashplate 5U and Wabbler 55 in whichslippers 54 operate, so that the slippers 54 may always be immersed inan oil bath.

In Fig. 6, swashplate 60 is xed on shaft 6I in any suitable manner, theshaft passing thru central spherical boss 62 of swashplate 6U.I Workingfaces 63 of swashplate 60 are spherical and coact with `similarspherical bearing faces of Wabbler 65 which comprises two members heldtogether embracing swashplate 60 in any suitable manner as by bolts 66,Wabbler 65 has arms 61 for operable connection with piston members in asimilar manner to'those shown in Figs. 1 and 3. Oil holes 68 serve tolead oil from hollow shaft 6I 'to the working clearance betweenswashplate 60 yand wabbler65, the entrance of oil into this clearancespace being at unloaded regions, as shown in an .exaggerated mannen InFig. 7, swashplate member 10 comprises two similar parts 10a and 10bwith spherical boss 10c clamped between them on shaft 1I in any suitablemannen Wabbler 15 is piloted on spherical boss 'IlleV and has conicalbearing surfaces operably engaging the conical working faces ofswashplate members 10a and 10b. Wabbler 15 has arms 'I1 for operableconnection with piston members in a similar manner to those shown inFigs. 1 and 3. Oil holes 'I8 serve to lead oil from hollow shaft 'II tothe working clearance between swashplate 10 and Wabbler 15, the entranceof oil into this clearance space being at unloaded regions; as shown inan exaggerated manner.

In operation; since the loading found in a Wabbler mechanism as a resultof piston action produces a couple or moment as indicated by the arrowsin Fig. 6 or 7, tending to overturn the Wabbler. This action is resistedby the swashplate, The loaded area of the swashplate is on the portionsof the working surfaces which lean toward the shaft. The Wabbler, beingpiloted on a spherical boss, bears heavily against these nearer portionsof the swashplate surfaces, leaving the opposite portions free, asindicated in Figs. 6 and 7. It is therefore obvious that eachv annularswashplate working surface, with its corresponding wabbler bearing area,if developed, would show convergence and divergence of the surfacessimilarto that well-known in a journal bearing. Since oil bathes theparts at all times, being constantly supplied under pressure, oil canreadily enter where the surfaces are not loaded, and be dragged into theconverging space, to form oil-wedge film lubrication exactly as in ajournal bearing.

While the foregoing relative positioning of the swashplate and wabbleris not essential whenv slippers are used as in Figs. 4 and 5, thepivoting of the wabbler on the spherical boss portion of the swashplateis decidedly helpful in the process of transferring the loading from oneslipper to the next as the swashplate turn's.

It is obvious also that swashplate members of any of the types shown maybe completely machined without any diinculty. The hole thru the boss andthe facing around the ends thereof is readily machined relative to theshaft axis, while the outer surface of the boss and the lworking facesare easily machined relative to the swashplate axis. The spherical bossalso provides the axial length of hole necessary to permit enough lengthof key or splines to transmit the torque to the shaft, without undulyhigh loading.

While spherical working faces of the type shown in Fig, 6, and conicalworking faces as shown in Fig. 7, in either inversion of the mechanisrn,are self-centering, it is not absolutely Ynecessary that the sphericalboss be provided.

It is however much better that the spherical boss pilot the wabbler andtake its radial loading, to permit the wabbler to assume its optimumposition relative to the swashplate, even tho the working clearancesshould be excessive as indicated in Figs. 6 and 7.

Having thus described the invention, it is b-y vious that the objectsthereof have been attained. While specific embodiments of the inventionhave been shown and described, it is understood that changes may be madein the construction and in the arrangement of the various parts, withoutdeparting from the spirit or scope of the following claims.

I claim:

1. In mechanism of the class described, a shaft, swashplate means fixedon saidv shaft, a pair o-f plan'e working surfaces on said swashplatemeans and a spherical pilot surface'associated with said workingsurfaces, a wabbler, bearing elements carried by` said wabbler andoperably conforming to said plane and spherical swashplate surfaces,said wabbler` being substantially U-shaped in section to contain an oilbath for flooded lubrication of saidbearing elements.

2. In mechanism of the class described, a

shaft, swashplate means fixed on said shaft, plane A working surfaces onsaid swashplate means and a spherical pilot surface on said swashplatemeans surrounding said shaft, a wabbler piloted on said spherical pilotsurface, bearing slippers pivoted in said wabbler in operablerelationship with said plane working surfaces, said wabbler beingsubstantially U-shaped in section to contain an oil bath for the floodedlubrication of said bearing slippers.

3. In a wabbler mechanism, a straight shaft, swashplate means fixed uponsaid shaft with the axis of said means inclined to and intersecting theaxis of said shaft, plane Working surfaces on said swashplate means saidsurfaces being normal to .the axis of saidswashplate means, asubstantially spherical boss associatedwith said swashplate means Withits center at the intersection of said axes, said shaft passing thrusaid boss, a wabbler operably associated with said swashplate means, andmeans for maintaining lubricant between-said swashplate means and saidwabbler.

4. In a wabbler mechanism, a straight shaft, swashplate means fixed uponsaid shaft with the axis of said means inclined to and intersecting theaxis of said shaft, spherical working surfaces on said swashplate means,a substantially spherical boss associated with said swashplate meanssaid shaft passing thru said boss, a wabblerv operably associated withsaid swashplate means, and means for maintaining lubricant between saidswashplate means and said wabbler.

5. In a wabbler mechanism, va straight shaft, swashplate means fixedupon said shaft with the axis of said means inclined to and intersectingthe-axis of said shaft, conical working surfaces on said swashplatemeans, a boss associated with said swashplate means with its center atthein tersection of said axes, said shaft passingthru said boss, awabbler operably associated with said swashplate means, and means 'formaintaining lubricant between said swashplate meansy and said wabbler. Yi

6. In a wabblermechanism, a straight shaft, swashplate means fixed uponsaid'shaft; with the axis ofsaid means inclined to and intersecting theaxis of said shaft, conical working surfaces on said swashplate means,the'conical axes coinciding with the axis of said swashplate'means, awabbler operably associated with said 'swashplate means, bearingsurfaces on said wabblercoacting with said conical working surfaces, andmeans for maintaining 'the working clearance between said bearingsurfaces and said conical working surfaces full ofnoil during operationof said mechanism. y'

7. In a wabbler mechanism, Va, straight shaft, swashplate means `fixedupon said shaft with the axis of said rn'eans inclined to andintersecting the axis `of said shaft, Working surfaces on saidswashplate meanssaidsurfaces being surfaces of revolution relative tothe axis of said'swashplate means, a substantially spherical bossassociated with said swashplate means with its center at theintersection of said axes, said shaft passing thru said boss, a wabbleroperably mounted on said swashplate means, slippers pivoted in saidWabbler and operably engaging said swashplate said wabbler full oflubricant during operation of said mechanism. A

8. In mechanisml of the class described, in combination, a straightshaft, swashplate means fixed upon said shaft and rotatable therewith,the exterior surfaces of said swashplate means being surfaces ofrevolution relative to an axis inclined to and intersecting the axis ofsaid shaft, said surfaces including a spherical surface centering at theintersection of said axes and Working surfaces substantially normal tosaid inclined axis, a wabbler piloted on said spherical surface, bearingmeans on said wabbler operably engaging said Working surfaces to supportthrust components of wabbler loading thereon, and means for leading oilinto the working clearance between said swashplate working surfaces andsaid wabbler bearing means.

9. In mechanism of the` class described, in

combination, a straight shaft, swashplate means fixed upon said shaftand rotatable therewith, the exterior surfaces of said swashplate meansbeing surfaces of revolution relative to an axis inclined to andintersecting the axis of said shaft, said surfaces including workingsurfaces 4substantially normal to' said inclined axis, a wabblerrotatable relative to said swashplate means, bearing means on saidwabbler operably engaging said swashplate Working surfaces, the loadingon said wabbler comprising a couple tending to rotate said'wabblersubstantially about the intersection of said axes to cause rotation ofsaid swashplate swashplate with its center Vat the intersection" of saidaxes, a wabbler comprising two similar parts .piloted on said boss andenclosing said swashplate and operably engaging said working surfaces,and means for maintaining the working clearance between said wabbler andsaid swashplate full of oil.

11. In a wabbler mechanism, in combination, a straight shaft, swashplatemeans comprising two similar parts fixed upon said shaft and a sphericalboss between them, the axis of said swashplate means inclined to andintersecting the axis of said shaft at the center of said sphericalboss, working surfaces on said swashplate means said surfaces beingsurfaces of revolution about and substantially normal to the axis ofsaid swashplate means, a wabbler piloted on said boss between the twosimilar parts of -said swashplate means, bearing means on said wabbleroperably engaging saidworking surfaces of said swashplate means, andmeans for maintaining said bearing means flooded with oil duringoperation of said mechanism.

12. In a wabbler mechanism, in combination,

a straight shaft, a swashplate xed upon said shaft and rotatabletherewith, the axis of said swashplate inclined to and intersecting theaxis of said shaft, plane working surfaces 0n said swashplate and normalto the axis thereof, a central spherical boss on said swashplate withits center at the intersection of said axes, a wabbler comprising twosimilar parts piloted on said boss and enclosing said swashplate andoperably engaging said working surfaces, and means for leading oil intothe working clearance between said swashplate working surfaces and saidwabbier.

13. In a wabbler mechanism, in combination, a straight shaft, swashplatemeans comprising two similar parts fixed upon saidyshaft and a sphericalboss between them, the axis of said swashplate means inclined to andintersecting the axis of said shaft at the center of said sphericalboss, plane working surfaces on said swashplate means said surfacesbeing normal to said inclined axis, a wabbler piloted on said sphericalboss between the two similar parts of said swashplate means, bearingmeans on said wabbler operably engaging said plane working surfaces ofsaid swashplate means, and means for maintaining said bearing meansflooded with oil during operation of said mechanism.

14. In combination with a straight shaft, swashplate means inclined toand fixed upon and rotating with said shaft, all surfaces of saidswashplate means except those resisting relative rotation thereof onsaid shaft being surfaces of revolution relative either to the inclinedaxis of said swashplate means or to the axis of said shaft or to both, awabbler operably mounted with suitable working clearance upon saidswashplate means, and means for introducing oil in the regions in saidclearance which are normally unloaded during operation and formaintaining said clearance full of oil. Y

15. Structure as claimed in claim 8 in which said working surfaces areplane and normal to said inclined axis.

16. Structure as claimed in claim 8 in which said working surfaces arespherical and nonconcentric their centers on said inclined axis.

17. Structure as claimed in claim 8 in which said working surfaces areconical.

18. Structure as claimed in claim 9 in which said working surfaces areplane and normal to said inclined axis.

19. Structure as claimed in claim 9 in which said working surfaces arespherical and non-concentric their centers on said inclined axis.

20. Structure as claimed in claim 9 in which saidv working surfaces areconical, the axes of the cones coinciding with said inclined axis.

EDWIN S. HALL.

